Potential impacts of land use change on streamflow and groundwater resources under changing climate in the Flint River Basin, Georgia, United States

Abstract

This study ascertains the factors affecting streamflow and irrigation water demand under different land use/cover (LULC) changes and future climate scenarios in the Flint River Basin, Georgia, United States, using the seemingly unrelated regression (SUR) panel model. An advantage of using the SUR model is that it accounts for cross-hydrological correlation, which is important due to the cross-sectional dependence between streamflow and pumpages. A set of streamflow, ground/surface water withdrawal, climatic, and LULC data used in this study was gathered from publicly available data sources and state agencies. Furthermore, the results show that a 10% increase in corn acreage in the watershed could lead to a significant rise in surface water and groundwater pumpings demands, respectively at 124% and 168%. This study identifies potential evapotranspiration (PET) threshold, which may lead to a water deficit in the region. For various LULC scenarios involving corn and urban area expansion, the probability of facing water scarcity at least once from 2025 to 2060 is estimated to range from 0.2% to 3.8% and 0.7% to 2.6% under RCP 4.5 and RCP 8.5 scenarios, respectively. These findings underscore the trade-off between water scarcity and food security in the context of changing climate, highlighting a need to design appropriate incentives to enhance water-use efficiency and adopt climate-smart strategies. The study’s significance extends to other similar watersheds worldwide that face similar challenges arising from changing land use and climate, which impact the sustainability of water resources, particularly groundwater resources, over time.